[leetcode 289]Game of Life
阿新 • • 發佈:2019-02-18
According to the Wikipedia's article: "The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970."
Given a board with m by n cells, each cell has an initial state live (1) or dead (0). Each cell interacts with its eight neighbors
- Any live cell with fewer than two live neighbors dies, as if caused by under-population.
- Any live cell with two or three live neighbors lives on to the next generation.
- Any live cell with more than three live neighbors dies, as if by over-population..
- Any dead cell with exactly three live neighbors becomes a live cell, as if by reproduction.
Write a function to compute the next state (after one update) of the board given its current state.
Follow up:
- Could you solve it in-place? Remember that the board needs to be updated at the same time: You cannot update some cells first and then use their updated values to update other cells.
- In this question, we represent the board using a 2D array. In principle, the board is infinite, which would cause problems when the active area encroaches the border of the array. How would you address these problems?
Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.
給定一個由0,1組成的矩陣,每一個元素表示一個細胞的存活,1存活,0死亡,其中下一次更新每個細胞的存活由上、下、左、右、左上、左下、右上、右下,八個細胞決定,存活規則如下:
1、周圍存活細胞小於2個,則死亡。
2、周圍存活細胞2個或3個,則存活到下一次更新。
3、周圍存活細胞3個以上,則死亡。
4、周圍存活細胞3個的死細胞,將會成為一個活細胞。
AC程式碼:
class Solution
{
public:
void gameOfLife(vector<vector<int>>& board)
{
int rows=board.size();
if(rows==0)
return ;
int colums=board[0].size();
if(colums==0)
return ;
for(int i=0; i<rows; ++i)
{
for(int j=0; j<colums; ++j)
{
int sum=getNeighbor(board,rows,colums,i,j);
if(sum==2)
continue;
else if(sum==3)
board[i][j]=board[i][j]==0?3:1;
else
board[i][j]=board[i][j]==1?2:0;
}
}
for(int i=0;i<rows;++i)
{
for(int j=0;j<colums;++j)
board[i][j]%=2;
}
}
private:
int getNeighbor(vector<vector<int>>& board,int rows,int colums,int x,int y)
{
int sum=0;
for(int i=x-1; i<x+2; ++i)
{
for(int j=y-1; j<y+2; ++j)
{
if(i==x&&j==y)
continue;
if(i>=0&&i<rows&&j>=0&&j<colums&&(board[i][j]==1||board[i][j]==2))
++sum;
}
}
return sum;
}
};
其他leetcode題目AC程式碼:https://github.com/PoughER